this time something totally new for the 49ers and the nfl. you probably know by now, sibling rivalry, two brothers coaching against each other in the super bowl. we have extensive coverage tonight of the super bowl. jim kozemore in our newsroom. we begin with arturo santiago with the family angle. >> reporter: you could say john harbaugh has had bragging rights since they beat the 49ers on thanksgiving day in 2011. now that very same sibling rivalry will be played out on an even bigger stage, the super bowl. >> i feel like there's no losing in that family. and i'm sure the brothers feel the same way. but one of them's going to win. >> reporter: tina knows a little something about sibling rivalry, the mother of twin boys who are now in college who have been competing against each other from day one. >> they don't look to other people as competition. they look at each other and they say, okay, can i beat you? and then once i beat you, i can do whatever to get the next group of guys. bring them in. >> reporter: psychologist dr. marc steinberg sa